Celiac? Negative colonoscopy maybe postive endoscopy?

Hi my husband has had a negative blood test in novemeber for celiac in routine doctors appt, had a colonoscopy all clear bar diviticlosis, biopsy came back nothing. Endoscopy all normal taken 4 biopsys to rule out celiac and due to weight loss? 

My question is can it be celiac if it didn't come up in colonoscopy? So confused and stressed out.